Rubbing shoe



July 5, 1955 R. J; cHAMPAYNE 2,712,206

RUBBING SHOE Filed June 16, 1952 United States Patent ffiee Z,71Z,20$ Patented July 5, 1955 RUBP'ING SHOE Roy J. Champayne, Rockfoi'd, Ill.

Application June 16, 1952, Serial No. 293,799

12 Claims. (Cl. 51-187) i This inverition relates to a rubbing shoe secured on its upper side to a support and providing on its underside a hacking for one or more rubbing sheets bent upwardly and around the shoe ends and held by clamps on the upper side of the shoe.

The primary object of the invention is to provide a rubbing shoe of the above Character having a new and improved clamp positively actuated by a toggle mechanism construeted and arranged in a novel manner to move over-center in closing the clamp in spite of wide variations in the thickness of the stack ofl rubbing sheets to be gripped between the jaws of the clanip.

A further object is to arrange the toggle for closing ing levei' iii a novel manner in relation to the rubbing shoe so as to dispose all of the parts compactly in an out of the way position when the clamp is closed.

A further object is to arranged the toggle for closing of the clanip by the application of hand pressure to the actuating lever downwardly and toward the top of the rubbing shoe.

The invention also resides in the yieldable construction of the clamp, the toggle, and the toggle mounting to permit different numbers of rubbing sheets to be held securely between the clarnp jaws.

Other objects and advantages of the in-vention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which Figure 1 is a fragmentary perspective view ofa rubbing machine equipped with a clai'np embodying the novel e the resent inventioii. ll. Z is a fragmentary side view with broken away and showing the clamp in the. open position. 1. k

Fig. 3 is aperspective view of one of the toggle 1nn s.

Fig. 4 is a perspective view of a portiorrof 'the ciamp.

Fig. 5 is a view similar to Fig. 2 showing the clamp sition. gif i a ragnentary view of the clamp illnstrating f the to le. lii g iga view imilar to Pig. illustrating the manner in which the clamp grips a plurality of rubbingrshee ts.

In the drawings, the invention is shown associated with a rubbing shoe adapted to be act uated either marually or by power and secured to a suitable support li up standing from the upper side of the shoe. The body o the shoe comprises a generally rectaiigular and relatively rigicl plate 12 having secured to the .underside thereof a pad 13 of yieldable material providing a hacking for o ne or more sheets 14 of abrasive paper or other rubbing l. lie abrasive sheets 14 are somewhat longer than the shoe 10 so that their end portions 15, after being bent upwardly and around the end 16 of the shoe, project a short .distance over the top of the shoe for entry between the jaws ofja clamp 17 which is mounted on top of the shoe and opens generally outwa-rdly toward the shoe end. The fixed jaw 18 of the clamp is rigid with the upper side of the shoe 10 and preferably is iiiclined upwardly away from the shoe end 16. Herein, this jaw is formed by one leg of an angle bracket 19 (Fig. 4) stamped from Sheet metal and having an upright leg 20 lying alongside the Vertical front wall 21 (Fig. 2) of the support 11 and secured to the latter by suitable screws 22.

The movable jaw 23 (Fg. 2) of the clamp comprises a pad 24 of resilient'ly yieldable material such as relatively firin rubber disposed above the fixed jaw 18 parallel to the shoe end 16 and baeked by a metal bar 25a which is pivotally inounted on the support 11 to turn toward and away from the fixed jaw about a horizontal axis a paralleling the end 16 of the shoe 10. Lugs-26 integral with the pad ai'e pressed through holes in the plate to secure the pad thereto. To define the pivotal axis a, edge portions 27 at opposite sides of the bracket 19 extend upwardly along the wall 21 and are curled around a pintle 28 that spans the two curls in front of the bracket leg 20. i

The jaw 23 is thus swingable downwardly against the rubbing slieet 14 (Fig. 5) or a Stack thereof (Fig. 7) bent upwardly and around the end of the shoe with the end or ends lying against the fixed jaw 18. Comparing Figs. 5 and 7, it will be observed that the movable jaw 23 may, when the clamp is closed, occupy a number of different positions depending on the number and thickness of the rubbing sheets being clamped.

In accordance with the present invention, the substantial force required for claniping the rubbing sheets is derived by straighteniiig of a toggle mechanism 32 to an over-center position which position is substantially the same for all of the different positions of the movable jaw 23 thus maintaining a uniform clarnping force in spite of the relatively Wide differencein the position of' the jaw when clamping a single Sheet as in Fig. 5 and a nuinber of sheets as in Fig. 7. Thus the actuation of the 'clamp 17 is positive rather than being derived from the action of a spring. Herein the toggle 32 comprises a first link 33 pivoted at one end to the outer free end of the movable jaw arm 23 to turn relative to the lattei' about an axis b parallel to the axis a and a second link pivotally mounted at one end on the support 11 to swing about another parallel axis c. At their outer free ends, the two links are pivoted together to form the toggle pivot 34.

The toggle 32 has an over-center action, that is the i toggle pivot 34 moves from one side of a line e (Fig. 6),

which is defined by the axes b and c, to the other. When the toggle is'flexed so that the links 33 and 35 are at an angle with respect to each other as shown in Fig. 2, the clamp 17 is open. As the toggle pivot is moved toward the-support wall 21, the toggle is straightened swinging the movable jaw 23 down toward the fixed jaw 18 and, when the toggle pivot lies along the line e, the clamp is closed. The toggle pivot then is inoved slightly beyond the line e as shown in Fig. 6. With the toggle pivot moved over-center, the clamping pressure, which tends to swing the movable jaw 23 upwardly, cannot cause the toggle pivot to move back across the center line e and thus the clamp 17 is locked in the closed position.

When additional thicknesses of rubbing sheets 14 are held by the clamp' 17, the movable jaw 23 cannot swing down as far as it did when clampng a single sheet and stops short of its former position as seen in Fig. 7. To permit the over-center action of' the toggle 32 Vin such a case, the toggle is yieldable. For this puipose, the link l33v is made of a reslient material such as spring steel and is supported between the link 35 and the arm 23 to bow inwardly toward the front wall 21 of the support 11. In .order to support the link 33 for such bowing, the ends of the link are bent outwardly to form curls 37 and 38. Oneither side of the curl 37, the outer end of the plate 25a is bent upwardly to form alined curls 39 and a pivot pin 40 -extends through the curls 37 and 39 whereby the amaaoe o arm 25 and the link 33 may pivot relative to each other about the axis b. Similarly, a pivot pin 41 (Pig. 2) projects through the curl 38 at the other end of the link 33 with its ends fixed to depending fianges 42 on the link 35 and permits the toggle links to turn relative to each other about the axis d defining the toggle pivot 34.

With the above construction, the link 33 is ofiset inwardly from its pivotal aXes b and d and bows inwardly when endwise forces are applied at its axes. Thus, when a plurality of sheets are being clamped, the movable jaw 23 presses against the sheets before the toggle 32 is straightened and further movement of the toggle pivot 34 results in the application of such endwise forces to the link 33 which then bows. This bowing, in effect, shortens the length of the toggle between the axes b and c to permit the toggle pivot to move over center.

To permit even greater thicknesses of rubbing sheets 14 to be received between the jaws 18 and 23, the mounting of the toggle 32 also is yieldable. Herein, the yieldable mounting is obtained by pivoting the inner end of the link 35 to a yieldable strip 43 which is integral with the bracket leg 20 at the upper end thereof and is bent first outwardly away from the wall 21 and then upwardly generally parallel to the wall. A curl 44 formed on the upper end of the strip 43 projects between the fianges 42 on the link 35 and a pin 45 received in the curl is secured at its ends to the flanges and defines the axis c. With this mounting of the toggle 32, the aXis c will Shift away from the fixed jaw 18 as the clamp 17 is closed to permit the toggle pivot 34 to move across center.

In the present instance, advantage is taken of the mounting of the toggle 32 to close the clamp 17 by the application of hand pressure downwardly toward the top of the rubbing shoe 10 so that the sheets 14 may be clamped in place while the shoe is resting on a table or other firm support. For this purpose, the link 35 is extended outwardly beyond the toggle pivot 34 to form a handle 31 the outer free end of which is bent upwardly to form a thumb tab 36. Thus the handle 31 and the link 35 constitute a lever arm 3d which when depressed moves the toggle pivot in the clamp closing direction and which may be lifted to open the clamp 17. When the clamp is closed, the handle projects downwardly alongside the support wall 21 where it is out of the way during service use of the rubbing machine.

It will be observed that the above clamp is capable of holding securely either a single rubbing Sheet 14 or a plurality of sheets. Such versatility is achieved by the combined effects of the bowing of the link 33 and the bending of the strip 43 so that both the toggle 32 and the mounting of the toggle yicld. Due to the resilient nature of the pad 24, still further yielding is obtained. With this arrangement, it has been possible to clamp not only a single sheet but also a substantial number of sheets at one time. In addition, the over-center action of the toggle holds the clamp 17 open and permits the operator to use both hands to insert the ends of the sheets between the jaws 18 and 23. By virtue of the fact that the handle 31 is pressed downwardly to close the clamp, it is not necessary for the operator to hold the rubbing machine while clamping the sheets since the machine may rest on a table when the clamp is being closed. Although the handle 31 may be comparatively long to afford good leverage, it lies alongside the support wall 21 and is out of the way when the clamp is closed.

I claim as my invention:

1. In a rubbing machine, the combination of, a rubbing shoe providing a hacking surface on the under side thereof, a support upstanding from the upper side of said shoe and spaced inwardly from one end of the shoe, means on said upper side providing a generally upwardly facing fixed jaw between said end and said support, an arm pvoted on said support to swing about an axis parallel to said end and projecting outwardly over said fixed jaw, a pad of yieldable material fast on the under side of said arm and opposing said fixed jaw to provide a movable jaw, a toggle comprising a first link pvoted on the outer free end of said arm and extending upwardly therefrom and a second link pvoted on said support above said arm and extending outwardly from the support, the pivotal axes of said links being parallel to said first axis and said links being pvoted together adjacent their outer free ends to form the toggle pivot, and a handle rigid with and extending outwardly from said second link to be pushed downwardly thereby to move said toggle pivot across the center of said toggle and to swing said movable jaw toward said fixed jaw.

2. The combination of, a shoe for hacking a rubbing sheet, a jaw fixed to one end of said shoe, an arm pvotally mounted for movement toward and away from said fixed jaw, a pad of resilient material on said arm and opposing said fixed jaw to constitute a movable jaw, said jaws coacting to form an outwardly opening clamp, a toggle pvoted at one end to said arm, a resilient member joining the other end of said toggle to said shoe to permit bodily yielding of the toggle relative to the shoe, a handle movable relative to said shoe, and a connection between said handle and said toggle to move the latter from a fiexed to a substantially straight over-center position to close said jaws together, said toggle including a link composed of resilient material and bowed in the movement of the toggle over center after clamping of a rubbing sheet between said jaws.

3. The combination of, a shoe for hacking a rubber sheet, a jaw fixed to one end of said shoe, a second jaw mounted for movement toward and away from said fixed jaw and coacting therewith to form an outwardly opening clamp, a toggle pivoted at one end to said movable jaw, a resilient member joining the other end of said toggle to said shoe to permit bodily yielding of the toggle relative to the shoe, a handle movable relative to said shoe, and a connection between said handle and said toggle to move the latter from a flexed position to a substantially straight and over-center position to close said jaws together, said toggle including a link composed of resilient material and bowed in the movement of the toggle over center after clamping a rubbing Sheet between said jaws.

4. In a rubbing machine, the combination of, a rubbing shoe providing on the under side, a backing surface for a rubbing Sheet, a support upstanding from the upper side of said shoe and spaced inwardly from one end of the shoe, means on said upper side providing a fixed jaw adjacent said one end, an arm pvoted on said support to swing about an axis parallel to said end and extending outwardly over said fixed jaw to provide a movable jaw, a first link disposed above said arm and pvoted on said support to swing about an axis paralleling said first axis, a second link of yieldable material extending between the outer free end of said first link and the outer free end of said arm, means pivotally connecting one end of said second link to the adjacent end of said first link and the other end of the second link to the adjacent end of said arm and supporting said second link for bowing inwardly toward said support when endwise forces are applied to its ends by said first link and said arm, said links constituting a toggle, and a handle on one of said links to move said toggle to a substantially straight and over-center position thereby to swingV said movable jaw toward said fixed jaw and clamp the ends of different' numbers of rubbing sheets between the jaws, said second link bowing inwardly to accommodate different thicknesses of sheets.

5. The combination of, a shoe for backing a rubbing sheet, a jaw fixed to one end of said shoe, a second jaw mounted for movement toward and away from said fixed jaw 'and coacting therewith to form an outwardly opening clamp, a handle movable relative to said shoe, a toggle comprising two links pvoted together at adjacent ends, the opposite end of one link being pvoted to said movable jaw and the opposite end of the other link being pivotally connected to said s'noe, and a connection between said handle and said toggle to move the latter from a flexed to a substantially straight over-center position to close said jaws together, one of said links being of resilient material and laterally offset from its pivotal axes to bow in the movement of the toggle over center after clamping a rubbing sheet between said jaws.

6. In a rubbing machine, the combination of, a shoe for hacking a rubbing sheet, a jaw fixed to one end of said shoe, a second jaw mounted for movement toward and away from said fixed jaw and coacting therewith to form an outwardly opening clamp, a handle movable relative to said shoe, a toggle connected to said movable jaw, and a connection between said handle and said toggle to move the latter from a flexed to a substantially straight over-center position to close said jaws together, said toggle including a link composed of resilient material and bowed in the movement of the toggle over center after clamping a rubbing sheet between said jaws.

7. The combination of, a rubbing shoe providing a backing surface for a rubbing sheet on the under side thereof, a support upstanding from the upper side of said shoe and having a wall spaced from and facing outwardly toward one end of the shoe, means on said upper side defining a fixed jaw ajacent said one end, an arm pivoted on said support to swing about an axis parallel to said end and extending outwardly over said fixed jaw to provide a movable jaw, a yieldable strip dsposed above said arm and extending along but spaced from said wall with its lower end secured to the wall, a toggle comprising two links pivoted together at adjacent ends to form a toggle pivot, means pivotally mounting one of said links at the opposite end to the upper end of said strip, and means pivotally mounting the other link at its opposite end to the outer free end of said arm, the pivotal axes of said toggle being parallel to said first axis thereby to swing said movable jaw toward said fiXed jaw when said toggle is moved to a substantial straight and overcenter position while said yieldable strip bends toward said wall to permit different numbers of rubbing sheets to be clamped between the jaws.

8. The combination of, a shoe for backing a rubbing Sheet, a jaw fixed to one end of said shoe, a second jaw mounted for movement toward and away from said fix'ed jaw and coacting therewith to form an outwardly opening clamp, a toggle pivoted at one end to said movable jaw, a resilient member joining the other end of said toggle to said shoe to permit bodily yielding of the toggle relative to the shoe, a handle movable relative to said shoe, and a connection between said handle and said toggle to move the latter from a flexed position to a substantially straight and over-center position to close said jaws together.

9. In a rubbing machine, the combination of, a shoe for hacking a rubbing sheet, a jaw fixed to one end of said shoe, a second jaw individually mounted on said shoe for movement toward and away from said fiXed jaw and coactng therewith to form an outwardly opening clamp, a handle movable relative to said shoe, and means separately mounting said handle on said shoe and connecting the handle to said second jaw, said means comprising a toggle connected to said movable jaw and a connection between said handle and said toggle to move the latter from a flexed to a substantially straight over-center position to close said jaws together.

10. The combination of, a rubbing shoe providing on the under side a backing for a rubbing sheet and on the upper side a fixed jaw extending inwardly from the end of the shoe, a support upstanding from said upper side and spaced inwardly of said shoe end, an arm pivoted on said support to swing about a horizontal axis parallel to said shoe end and extending outwardly from said axis over said fixed jaw to provide a movable jaw, a second arm dsposed above said first arm and pivoted to swing about a second axis paralleling said first aXis, said second arm constituting a handle and being movable from a generally horizontal position downwardly to a second position alongside said support, and means connecting said arms to move said movable jaw toward said fixed jaw as said second arm is swung downwardly thereby to clamp between the jaws the end of a rubbing sheet bent upwardly around the end of said shoe.

11. The combination of, a rubbing shoe providing on the underside a backing for a rubbing sheet, a clamp opening toward one end of the shoe and comprising fixed and movable jaws mounted on the upper side of said shoe, a support upstanding from said upper side, an over-center toggle pivotally connected at one end to said movable jaw and at the other endto said support and operable to close said clamp when straightened, and a handle connected to said toggle and mounted Vto swing from a generally horizontal and inactive position to an active position down alongside said support to straighten said toggle and clamp the end of a rubbing sheet between said jaws.

12. The combination of, a rubbing shoe having an upwardly facing clamping surface on the upper side and adjacent one end of the shoe, a support upstanding from said shoe side and spaced inwardly from said end thereof, a lower arm pivoted on said support to swing about a first generally horizontal axis and toward and away from said surface, said arm projecting outwardly over said surface and cooperating therewith to define an outwardly opening clamp, an upper arm projecting outwardly from said support above said lower arm and pivotally mounted to swing about a second axis parallel to said first axis and into and out of a lower position alongside' said support, and a link pivotally connected at opposite ends to said arms for movement of said lower arm toward said surface to close said clamp in the downward movement of said upper arm and cooperating with the latter to define a toggle movable over center to maintain the closed condition of the clamp as the upper arm swings into said lower position.

Champayne Sept. 12, 1950 Hoy Nov. 14, 1950 

